1. Field of the Invention
This invention relates to an automatic processor for processing light-sensitive materials and more particularly to an automatic processor capable of automatically informing a time of replacing a filter provided to check the contaminations in a processing liquid.
2. Description of the Prior Art
Generally, an automatic processor is equipped with a thermostatic control means for keeping a processing liquid at a given temperature so that the finished image quality of a photographic light-sensitive material (hereinafter called simply a light-sensitive material) such as a photo film and a photoprinting paper may be maintained at a constant level.
The thermostatic control means comprises a heat exchanger provided onto a circulating flow path so arranged as to draw off a processing liquid from a processing liquid tank and to send it back again to the tank.
On the other hand, a piece of filter is used to satisfy one of the requirements for the stable processing of a light-sensitive material. It is needless to say that such a filter adsorbs gelatins or various additives eluted from the light-sensitive material being processed, chips of the light-sensitive material, dusts in the air and the like so that the processing liquid may consequently be kept uncontaminated. And yet, as a quantity processed is on the increase, the filter is clogged with dusts because the adhesion of dust thereto is increased. If this is the case, the filter cannot perform its own functions. In other words, the filter will disturb the circulation of the processing liquid so that a processing temperature cannot suitably be controlled and the finished image quality of the light-sensitive material is lowered resultantly.
It is, therefore, desired to replace filters regularly. Heretofore, however, there has not been found out any means for detecting a clogged filter, and such filters have been replaced periodically as prescribed in the instruction manual attached to an automatic processor. However, a period for producing clogs on a filter is varied according to how many light-sensitive materials processed, the quality of water and the like. It is, therefore, unsuitable that the replacements of filters are made at every prescribed period for operating an automatic processor. There may be some disadvantageous instances where, for example, a user may reluctantly replace a still usable filter, and a finished image quality of light-sensitive material may be lowered due to the delay in replacement that will make clogs serious. In addition to the above, there is another disadvantage that a user may sometimes forget to replace filters because the replacement period is stated only in the instruction manual of his processor.